LOF

The LOF function is used to find the length of an OPEN file in bytes, or content length of an HTTP response.

Syntax

totalBytes& = LOF([#]fileNumber)

totalBytes& = LOF([#]httpHandle)

Description

• For regular OPENed files:
  • LOF returns the number of bytes in an OPENed designated fileNumber. File is empty if it returns 0.
  • fileNumber is the number of the opened file. # is not required.
  • Often used to determine the number of records in a RANDOM access file.
  • Can also be used to avoid reading an empty file, which would create an error.
  • LOF in QB64 can return up to 9 GB (9,223,372,036 bytes) file sizes.

• For HTTP handles opened using _OPENCLIENT:
  • LOF returns the length listed in the Content-Length header of the HTTP response.
  • If no Content-Length header was provided on the HTTP response, then LOF return -1

Examples

Example: Finding the number of records in a RANDOM file using a TYPE variable.

OPEN file$ FOR RANDOM AS #1 LEN = LEN(Type_variable) NumRecords% = LOF(1) \ RecordLEN%

Example: Reading the Content length of an HTTP response

$UNSTABLE:Http h& = _OPENCLIENT("HTTP:https://qb64phoenix.com") PRINT LOF(h&)

See also

• LEN, EOF, BINARY, RANDOM, TYPE

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